From 37e6d3d810808be821162c44335a5e391c5fae07 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sat, 23 May 2020 11:20:33 +0800
Subject: [PATCH] add doc

---
 docs/lib2x-sum.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 docs/lib2x-sum.md

diff --git a/docs/lib2x-sum.md b/docs/lib2x-sum.md
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+# sum
+
+Use `+` to sum up all elements in a list.
+
+**Since:** 2.4
+
+## Parameters
+
+- `lt` : a list of elements that can be applied by `+`.
+
+## Examples
+
+    use <util/sum.scad>;
+
+    assert(sum([1, 2, 3, 4, 5]) == 15);
+    assert(sum([[1, 2, 3], [4, 5, 6]]) == [5, 7, 9]);